HR: 0800h
AN: H41C-0660    [Abstracts]
TI: Phosphorus fluxes in headwater streams draining non-research poultry-pasture operations in north-central Georgia, USA
AU: * Romeis, J J
EM: romeisj@warnell.uga.edu
AF: Warnell School of Forestry and Natural Resources, 1040 D.W. Brooks Drive, The University of Georgia, Athens, GA 30602, United States
AU: Jackson, C R
EM: rjackson@warnell.uga.edu
AF: Warnell School of Forestry and Natural Resources, 1040 D.W. Brooks Drive, The University of Georgia, Athens, GA 30602, United States
AU: Radcliffe, D E
EM: dradclif@uga.edu
AF: 3111 Miller Plant Sciences Building, 1040 D.W. Brooks Drive, The University of Georgia, Athens, GA 30602, United States
AU: Risse, M L
EM: mrisse@engr.uga.edu
AF: Department of Biological and Agricultural Engineering, 617 Driftmeier Engineering Center, The University of Georgia, Athens, GA 30602, United States
AU: Bryant, J
EM: jb2601@yahoo.com
AF: 3111 Miller Plant Sciences Building, 1040 D.W. Brooks Drive, The University of Georgia, Athens, GA 30602, United States
AB: Poultry production is the largest agricultural commodity in Georgia, USA. Due to inefficient utilization of the phosphorus (P) in poultry feed, the manure contains high concentrations of P. When used as fertilizer for crops and pasture, poultry manure may be washed from the soil surface and increase eutrophication risks to downstream lakes and reservoirs. Long term application of poultry manure may result in P saturation of the soils. In the upper Etowah River basin in north-central Georgia, a long history of poultry farming has resulted in high P levels in soils receiving regular poultry manure applications. Few studies to date have been performed on the estimation of P fluxes from operational commercial poultry farms in Georgia. In Fall 2006, a 20-month surface water quality monitoring program was completed that was aimed at estimating P and suspended sediment fluxes in nine headwater streams draining poultry-pasture operations in the upper Etowah River basin. The nine catchments differed in terms of land use history, soil P levels, best management practices and other factors. An additional three streams draining U.S. National Forest were also monitored to provide reference concentrations and loads. Monitoring data included continuous (5-minute) streamflow, rainfall, and water quality samples. Water quality samples included biweekly grab samples plus storm samples collected using conventional autosamplers. Storm sampling using autosamplers included collection of discrete samples and composite samples. In particular instances, the two types of storm sample were collected simultaneously. Discrete storm sampling methods enabled collection of both rising and falling hydrograph limb samples to identify potential hysteretic water quality effects. Water samples were analyzed for total P, filterable reactive P, and total suspended solids. We are using this data to compare different flux estimation methods with emphasis on regression models that utilize laboratory results of both discrete and composite samples as well as models using non- transformed data. Preliminary results demonstrate some success in the use of regression models from agricultural streams where P levels in stormflow are high. This may be partially attributed to the combination of the temporal resolution of the monitoring data plus the accommodation of sampling different flow regimes. In streams where concentrations and overall variability of P is low, averaging methods may be the most appropriate.
DE: 1804 Catchment
DE: 1834 Human impacts
DE: 1871 Surface water quality
DE: 1895 Instruments and techniques: monitoring
SC: Hydrology [H]
MN: 2007 Fall Meeting